This disclosure relates to a cleaning apparatus configured to remove residual toner or the like that remains on the surface of an image carrier member, and to an image forming apparatus mounting the cleaning apparatus.
An image forming apparatus using an electrographic method forms an electrostatic latent image on a photosensitive drum by use of an electric charger that applies a charge in advance to an image carrier member, for example, to a photosensitive drum, followed by irradiation of light onto the surface of the photosensitive drum with an exposure unit. Furthermore, a toner image is developed on the surface of the photosensitive drum by attachment of toner stored in a developing unit onto the electrostatic latent image. The image forming apparatus transfers and fixes the visualized toner image onto paper used for direct contact, or onto a sheet of paper via an intermediate transfer member.
Toner transfer onto the sheet may fail and result in residual toner on the surface of the photosensitive drum. Residual toner on the surface of the photosensitive drum must be removed before a subsequent image forming operation.
In this context, a related technique has been disclosed in which the surface of the photosensitive drum is cleaned.
More particularly, an image forming apparatus has been disclosed in which a cleaning blade and a cleaning roller are brought into contact with the surface of the photosensitive drum and the cleaning blade removes residual toner remaining on the surface of the photosensitive drum.
The related techniques include disclosure of a technique in which a tiny amount of abrasive contained in the residual toner is used and the cleaning roller uses the residual toner removed by the cleaning blade to remove a discharge product or the like that is attached to the surface of the photosensitive drum. Furthermore, the related techniques include disclosure of a technique applying in which the thickness of the toner attached to the cleaning roller is adjusted by contact of a scraper to the cleaning roller.
However, the related techniques include the unsolved problem of attaching and maintaining a suitable amount of residual toner to the cleaning roller.
This is due to the fact that adjustment of the toner amount is difficult since the scraper in this technique makes contact with the cleaning roller in a trailing direction and therefore there is a low capacity to peel and remove the residual toner from the cleaning roller.
Furthermore, since the scraper is formed in a film configuration, wear is caused by sliding on the cleaning roller.
On the other hand, a scraper has been proposed that is placed into contact with the cleaning roller in the counter direction. However, in this configuration, residual toner is continuously scraped and removed from the cleaning roller, and therefore residual toner cannot be retained on the cleaning roller.
When continuous printing of a low density printed pattern by the image forming apparatus is assumed, that is to say, during operating conditions in which attachment of the residual toner to the cleaning roller is difficult, provision of either type of scraper may result in failure to maintain the abrasive performance of the cleaning roller that is required to remove a discharge product.
In this manner, optimization of the toner amount attached to the cleaning roller requires a means or mechanism that enables constant maintenance of residual toner attached to the cleaning roller.